It is generally known that silver catalysts are applied in the oxidation of ethylene to ethylene oxide. See for example, U.S. Pat. No. 3,962,136, in which such silver catalysts are disclosed. Moreover there is disclosed in the application that small amounts of one or more promoters are present, such as cesium compounds, rubidium compounds and potassium compounds.
In co-pending U.S. patent application Ser. No. 874,913, filed Jun. 16, 1986, is disclosed a silver catalyst, in which the carrier was enriched with an alkali metal, such as cesium. The catalyst has a high stability in the reaction of ethylene with molecular oxygen to ethylene oxide.
Applicant has now found silver catalysts with improved selectivity and even higher stability.